Frame of a nasal mask

The design consists of the features of shape, ornament, pattern and configuration of a NASAL MASK shown in the drawings. The parallel break lines along the breathing tube of the article demonstrate that the breathing tube is of indeterminate length. The parallel break lines and the portions of the breathing tube between the break lines do not form a part of the design. Drawings of the design are enclosed in which: Figure 1 is a top, front and side perspective view of a NASAL MASK showing the design; Figure 2 is a front view thereof; Figure 3 is a rear view thereof; Figure 4 is a first side view thereof; Figure 5 is a second side view thereof; Figure 6 is a top view thereof; and Figure 7 is a bottom view thereof. Drawings of the design are included.